1. Field of the Invention
The present invention relates to a biplane type X-ray diagnostic apparatus enabling photographing (fluoroscopic imaging/radiographic imaging) in two directions.
2. Description of the Related Art
A biplane type X-ray diagnostic apparatus developed chiefly for use in circulatory system examinations is equipped with two photographic (fluoroscopic/radiographic) systems in order to achieve simultaneous photographing in two directions: one is a frontal photographic system that photographs a subject laid on his back on the diagnostic table top in the frontal plane, and the other is a lateral photographic system that photographs the subject in the lateral plane. The frontal photographic system includes an X-ray tube and an X-ray detector respectively attached to the both ends of a C-arm supported by a floor-standing stand. The lateral photographic system also includes an X-ray tube and an X-ray detector, which are respectively attached to the both ends of an Ω-arm suspended from the ceiling.
Because the stand is installed to the floor, the C-arm in the frontal system is allowed to swivel about the stand (strut rotation), but in principle, remains immovable with respect to the floor surface. On the other hand, the Ω-arm in the lateral system is attached to the strut suspended from a slider engaged with a rail laid on the ceiling, and is therefore provided movably along the rail. This arrangement enables single-plane photographing with the use of the frontal photographic system alone by retracting the lateral photographic system to a remote place.
In the case of a diagnostic of a cardiac region, the blood vessel formation or injection of an anti-cancer agent through a catheter manipulation by X-ray fluoroscopy, or IVR (interventional radiology) accompanying an operation, such as occlusion of the vessels of nutrition to tumor tissues, biplane photographing using both the frontal and lateral photographic systems and single-plane photographing using the frontal photographic system alone are switched over frequently.
The lateral photographic system needs to be retracted from a photographing position to an evacuation position and returned to the photographing position from the evacuation position each time the switching takes place. Moreover, in order to avoid the interference with operations of the frontal photographic system by the lateral photographic system at the evacuation position and to secure a sufficiently large working space for an operator, the evacuation position is set to a place as far as 3 m away from the photographing position. Hence, each time biplane photographing and single-plane photographing are switched over, an examination or an operation work is halted for not short a time needed to move the lateral photographic system between the photographing position and the evacuation position, and the work efficiency is deteriorated as a result.